Q. If a person sees Rasulullah (Sallallahu alayhi wasallam) in a dream wearing such clothes which were not worn during his time, will the dream be authentic? Did he in fact see Nabi (Sallallahu alayhi wasallam)?
A. The Akaabir Ulama/Auliya have different views on this issue. There are three views regarding seeing Rasulullah (Sallallahu alayhi wasallam) in a dream.
First view: Shah Abdul Azeez (Rahmatullah alayh) said that if one’s heart testifies that the one seen is Rasulullah (Sallallahu alayhi wasallam), then he has seen Nabi (Sallallahu alayhi wasallam) regardless in whatever form the vision is. There should be no doubt in the heart.

Second view: Shah Rafeeuddeen (Rahmatullah alayh) said that if there is even the slightest difference with Rasulullah’s actual form and appearance, then the one seen is not Rasulullah (Sallallahu alayhi wasallam). For example, if Rasulullah (Sallallahu alayhi wasallam) had 20 white hairs, and if the dreamer sees 21, then the one he sees is not Rasulullah (Sallallahu alayhi wasallam). The slightest difference in any form negates the authenticity of the dream.
In substantiation of his view, Shah Rafeeuddeen (Rahmatullah alayh) would say that during the age of the Sahaabah if anyone claimed to have seen Rasulullah (Sallallahu alayhi wasallam) in a dream, they would ask the person to describe the vision he saw. If the description differed even slightly from Rasulullah’s actual form and appearance they would reject it and say that it was not Rasulullah (Sallallahu alayhi wasallam).

Third view: Shah Ishaaq (Rahmatullah alayh) said that if one sees in a dream that Rasulullah (Sallallahu alayhi wasallam) is dressed in the garments of the Atqiya (the men of piety/Auliya) of the age, then he did see Rasulullah (Sallallahu alayhi wasallam). If he sees Rasulullah (Sallallahu alayhi wasallam) dressed in some other type of garb, then it is not Nabi-e-Kareem (Sallallahu alayhi wasallam).
From these differences it is clear that there is no absolute certitude on this issue. The criterion is always the Shariah. If anything in the dream is done or instructed that is in conflict with the Shariah, then it should be compulsorily set aside.
It will be haraam to give practical expression and to implement anything seen in a dream if it contravenes the Shariah regardless of whether the vision in the dream is that of Rasulullah (Sallallahu alayhi wasallam).
Dreams do not override the Shariah which Rasulullah (Sallallahu alayhi wasallam) had delivered to the Ummah from Allah Ta’ala.